Gas Sensor Inner Cover Louver Design for Cylinder Imbalance Detection
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Solution Overview
Problem
Conventional gas sensors for internal combustion engines have insufficient responsiveness to detect inter-cylinder air/fuel ratio imbalances due to the large distance measurement gases travel before reaching the sensor element, causing mixing of gases from different cylinders, which reduces detection accuracy.
Innovation Solution
A gas sensor design with an inner cover having an inner inlet opening positioned closer to the axial proximal end side than the gas introduction part of the sensor element, allowing measurement gases to reach the sensor element quickly and minimizing mixing, achieved by optimizing the axial distance and using a louver part to direct the gas flow towards the proximal end side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the inner inlet opening is positioned closer to the axial proximal end side than the gas introduction part, then the measurement gas travel distance is shortened and detection responsiveness is improved, but the structural design complexity increases
Solution Approach 1:
The element cover is divided into an inner cover and an outer cover with distinct functions. The inner cover contains the inner inlet opening positioned at its proximal end, while the outer cover provides the outer inlet opening. This segmentation allows optimization of gas flow path without complicating the overall structure, as each cover component is relatively simple but works together to achieve short gas travel distance.
Solution Approach 2:
The patent positions the inner inlet opening at the axial proximal end side of the inner cover, creating a three-dimensional arrangement where gas enters from the outer cover, flows axially through the inner cover, and reaches the gas introduction part. This spatial arrangement in multiple dimensions optimizes the gas flow path length while maintaining a compact overall structure.
2Measurement precision
If the measurement gas travel distance is large, then the sensor element is protected from flooding, but the detection accuracy of inter-cylinder imbalance is reduced due to gas mixing
Solution Approach 1:
The inner cover acts as an intermediary component between the outer cover and the sensor element. It receives measurement gas from the outer cover through the inner inlet opening and directs it to the gas introduction part. This intermediary structure allows precise control of gas flow path length and direction, enabling short travel distance for high detection accuracy while the outer cover continues to provide flooding protection.
Solution Approach 2:
The patent applies different structural qualities to different parts of the element cover. The inner cover has the inner inlet opening positioned at its proximal end to create a short, direct gas path for high measurement precision. The outer cover maintains its structure for flooding protection. This local optimization of different regions achieves both short gas travel distance and flooding protection simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the accuracy and responsiveness of detecting inter-cylinder imbalances by ensuring measurement gases from different cylinders reach the sensor element without mixing, thereby improving the detection of air/fuel ratios and reducing the risk of flooding.
Implementation Method 1
using a louver part to direct the gas flow towards the proximal end side
Data Source
AI summary
A gas sensor 1 includes a sensor element 2, a housing 13 and an element cover 3. The sensor element 2 is provided with a gas introduction part 271 for introducing a measurement gas thereinto at a distal end portion 201 thereof. The element cover 3 includes an inner cover 4 disposed so as to cover the distal end portion 201 of the sensor element 2 and an outer cover disposed outside the inner cover 4. The outer cover 5 is provided with outer inlet openings 52 for introducing the measurement gas into the outer cover 5. The inner cover 4 is provided with inner inlet openings 42 for introducing the measurement gas into the inner cover 4. The axial intermediate position C1 of the gas introduction part 271 of the sensor element 2 is more to the axial proximal end side X2 than the axial proximal end position D1 of the inner inlet opening 42 of the inner cover 4.